**7.3 Result interpretation**

	- 1. Initial fasting glucose within normal limits
	- 2.The highest value does not exceed the renal threshold (160-180 mg/dl (8.8-10 mmol/L))
	- 3.The fasting level is again reached by 2–2.30 hours
	- 4.No glucose or ketone bodies are detected in any urine specimen
	- 1.Fasting blood glucose may raise above normal usually in the impaired range
	- 2.The peak is reached between 1 and 1.30 hours
	- 3.Glucosuria is usually present because the highest value exceeds the renal threshold
	- 4.Plasma glucose does not return to fasting level within 2.30 hours, the most characteristic feature of DM response
	- 1.Normal Fasting glucose level
	- 2.Plasma glucose rises rapidly within 30 minutes to 1-hr post glucose ingestion exceeds renal threshold with corresponding glucosuria
	- 3.Return to normal quickly and completely
	- 4.This is usually noted in Hyperthyroidism, post gastroenterostomy, during pregnancy, early diabetes
	- 1.Glucose appears in the urine at normal plasma glucose much below renal threshold

*Oral Glucose Tolerance Test (OGTT): Undeniably the First Choice Investigation… DOI: http://dx.doi.org/10.5772/intechopen.96549*


Under certain pathological conditions such as hyper- and hypothyroidism changes in the gastric emptying rate may significantly alter the shape of the glucose tolerance curves [79]. Rapid gastric emptying associated with duodenal ulcer and partial gastrectomy where plasma glucose rises rapidly within 30 minutes of glucose ingestion stimulating hyperinsulinaemia and resultant reactive hypoglycaemia though measurement of serum insulin levels does not reveal evidence of such direct relationship.

In a healthy young adult with increase physiologic activities, there is associated rapid metabolism and when venous rather than capillary blood is analyzed, a flat curve can be a normal findings and not of either deficient absorption or slow gastric emptying. Hypoglycaemia in a fasting subject is normally prevented by hepatic gluconeogenesis. This stopped after glucose ingestion when blood glucose rises, and begun when plasma glucose is falling preventing fasting hypoglycaemia Reactive hypoglycaemia in either normal healthy young adult, patient with peptic ulcer or partial gastrectomy might, therefore, be due to the failure of the liver to resume glucose production sufficiently and rapidly. The normal exponential pattern of gastric emptying results in a very gradual decline of the rate at which glucose enters the intestine and this should provide ideal conditions for the liver gradually to resume glucose production. The absorption of glucose by the small intestine is highly efficient. After ingestion of a concentrated solution, a combination of slow gastric emptying, dilution within the duodenum, and active peristalsis ensure that within the jejunum the glucose solution no longer remains hypertonic. The small intestine is efficient in glucose absorption.

Every dynamic test requiring appropriate patient preparation and procedure for the conduct of the test will not be without contraindication if result is to be reliable. Such contraindications for conduct of OGTT are shown in **Table 6**. The primary objective is to demonstrate presence of dysglycaemia in a condition that has long latent period, except when monitoring success of treatment in secondary causes of hyperglycaemia. Subject must be conscious and alert to obey order (in both preparation and conduct of the test), in a no stressful condition, physically or otherwise. Patient should be able to take the stated amount or an equivalent and under influence of no other condition except what is being investigated for.


#### **Table 6.**

*Conditions under which OGTT should not be conducted or when procedure should be stopped.*

b. The result shows assessment of glucose tolerance at the time of the test only

d. Nor will result predict response to hypoglycaemic therapy or the current or

Therefore result will be better interpreted with the cognition of the above in

2.The highest value does not exceed the renal threshold (160-180 mg/dl

4.No glucose or ketone bodies are detected in any urine specimen

1.Fasting blood glucose may raise above normal usually in the impaired

3.Glucosuria is usually present because the highest value exceeds the renal

4.Plasma glucose does not return to fasting level within 2.30 hours, the

2.Plasma glucose rises rapidly within 30 minutes to 1-hr post glucose ingestion exceeds renal threshold with corresponding glucosuria

4.This is usually noted in Hyperthyroidism, post gastroenterostomy,

1.Glucose appears in the urine at normal plasma glucose much below renal

c. Results give only a qualitative idea of the average 24-hr blood glucose

and cannot provide any other information.

a. Normal response has the following characteristics:

1. Initial fasting glucose within normal limits

3.The fasting level is again reached by 2–2.30 hours

2.The peak is reached between 1 and 1.30 hours

most characteristic feature of DM response

3.Return to normal quickly and completely

during pregnancy, early diabetes

future risk of diabetes complications

*Type 2 Diabetes - From Pathophysiology to Cyber Systems*

(8.8-10 mmol/L))

b. Response of diabetic patient

range

threshold

c. LAG curve for oxyhyperglycaemia

d. Response for renal glycosuria

threshold

**128**

1.Normal Fasting glucose level

mind.

**7.3 Result interpretation**
